Risk Management and Derivative Instruments (Details 3) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Gains (losses) on Commodity Derivative Contracts
Cash payment on derivative contract settlement	$ (42,200)		$ (94,797)	$ 31,948
Gains (losses) on commodity derivative contracts - net	(19,293)	$ (31,467)	2,079	(54,140)
Not designated as Hedging Instrument
Gains (losses) on Commodity Derivative Contracts
Cash payment on derivative contract settlement	42,189	(17,138)	94,797	(31,948)
Unrealized net gains (losses)	$ (61,482)	$ (14,329)	$ (92,718)	$ (22,192)

The amount of cash received during the period on settlement of a hedge.

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of open agreements to purchase or sell mineral resources, energy, and agricultural products at some future point held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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